1. Field of the Invention
The present invention relates generally to a passenger conveyor, and more particularly to a driven wheel for a passenger conveyor, which is made of an engineering plastic material, and which is operated by a rotating force of a driving wheel of a driving terminal, thereby improving its durability and support force, as well as increasing its operational productivity.
2. Description of the Related Art
The conventional passenger conveyor 1 such as an escalator, moving walk, etc., includes a driving terminal 2 as a drive source of the conveyor, as shown in FIG. 1. The driving terminal includes a driving motor 3 to be powered from a power supply, and a reduction gear 4 for reducing the rotating speed of the driving motor 3. The reduction gear is connected to a transmission gear 7 by driving chains 8. The transmission gear 7 is mounted on one side of driving gears 6 which are installed on both ends of a rotating shaft 5 having a predetermined length to drive the driving gears 6.
The driving gears 6 installed on both the ends of the rotating shaft 5 are operatively connected to pallet chains having a predetermined length. The pallet chains are operatively connected to a driven gear 11 of a driven terminal. Therefore, the driving force of the motor is transmitted to the driven gear 11 of the driven terminal through the reduction gear 4, the driving gears 6, the transmission gear 7, and pallet chains 9. The pallet chains 9 are provided with a plurality of continuous pallets 12 having a predetermined length, on which a passenger or luggage is loaded.
As shown in FIGS. 2 and 3, a tension adjusting device 14 for controlling the tension of the pallet chains 9 is mounted on the driven terminal 10 on which driven gears operatively connected to the pallet chains 9 are provided. The tension adjusting device 14 controls the tension of the pallet chains 9 by changing the position of a rotating shaft 13 of the driven gear 11.
The operation of the passenger conveyor 1 as constructed above will now be described in detail. When the power is applied to the driving motor 3 from an external power supply (not illustrated), the motor operates, and the reduction gear 4 is driven by the driving motor 3. The driving force of the reduction gear 4 is transferred to the driving gears 6 connected to the reduction gear by the driving chains, so that the driving gear 6 is operated. With the operation of the driving gears 6, the pallet chains 9, operatively connected to the driven gear 11, are operated. Because the pallet chains 9 include a number of continuous pallets 12, a passenger or luggage can be transferred to a desired position. At the same time, a hand rail 15 which is installed on a side of protecting barrier 16 is operated at the same speed as that of the pallet chains 9.
It would be understood from the description that when the two driven gears in the driven terminal are mounted on both ends of the rotating shaft, it is very difficult to precisely maintain the tooth symmetry of the two driven gears connected to the ends of the driven gears. If the driven gears are mounted asymmetrically on both ends of the rotating shaft, this asymmetry causes the pallet chains operatively connected to the driving gear and the driven gear to have different levels of tautness. If the tautness of the pallet chains connected to the driven gears disposed on both ends of the rotating shaft are different, then the intervals between the steps will be irregular, so that the steps will be out of line. This deteriorates stability, thereby possibly rendering the conveyor inoperative. As a result, this causes the life of the passenger conveyor to be shortened and causes the supporting force between the pallet chains and the driving gear to deteriorate as well.